We found that bee venom acupuncture effectively protected dopaminergic neurons against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity, possibly through inhibition of Jun activation. Our results suggest that bee venom acupuncture could be a potential preventive agent for Parkinson's disease.

Parkinson's disease (PD) is caused by the selective loss of dopaminergic neurons in the substantia nigra (SN) and the depletion of striatal dopamine (DA). Acupuncture, as an alternative therapy for PD, has beneficial effects in both PD patients and PD animal models, although the underlying mechanisms therein remain uncertain. The present study investigated whether acupuncture treatment affected dopamine neurotransmission in a PD mouse model using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We found that acupuncture treatment at acupoint GB34 improved motor function with accompanying dopaminergic neuron protection against MPTP but did not restore striatal dopamine depletion. Instead, acupuncture treatment increased dopamine release that in turn, may lead to the enhancement of dopamine availability in the synaptic cleft. Moreover, acupuncture treatment mitigated MPTP-induced abnormal postsynaptic changes, suggesting that acupuncture treatment may increase postsynaptic dopamine neurotransmission and facilitate the normalization of basal ganglia activity. These results suggest that the acupuncture-induced enhancement of synaptic dopamine availability may play a critical role in motor function improvement against MPTP.

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It has been reported that acupuncture treatment reduced dopaminergic neuron degeneration in Parkinson's disease (PD) models. However, the mechanistic pathways underlying, such neuroprotection, are poorly understood. Here, we investigated the effects and the underlying mechanism of acupuncture in a mouse model of PD using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). First, we observed that MPTP-induced impairment of Akt activation, but not MPTP-induced c-Jun activation, was effectively restored by acupuncture treatment in the substantia nigra. Furthermore, we demonstrated for the first time that the brain-specific blockade of phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway, by intranasal administration of LY294002, a specific inhibitor of PI3K/Akt signaling pathway, significantly blocked acupuncture-induced dopaminergic neuron protection and motor function improvement. Our results provide evidence that PI3K/Akt signaling pathway may play a central role in the mechanism underlying acupuncture-induced benefits in Parkinsonian mice.

BackgroundGastrodia elata Blume (GEB), commonly used medicinal herb, has been reported as a promising candidate for neurodegenerative diseases such as Parkinson’s disease. The dopamine precursor, L-3,4-dihydroxyphenylalanine (L-DOPA), is the gold-standard drug for Parkinson’s disease, but long-term treatment results in the L-dopa-induced dyskinesia (LID). This study was undertaken to examine the beneficial effects of GEB on L-DOPA induced dyskinesia in 6-hydroxydopamine (6-OHDA)-induced experimental Parkinsonism.MethodsWe tested the effects of GEB on LID in 6-hydroxydopamine hydrochloride-hemiparkinsonian mice. To analyze the dyskinetic anomalies, we measured abnormal involuntary movement (AIM). Immunohistological analyses of pERK and FosB expressions in the striatum are performed to explore the mechanism of GEB on LID.ResultsThe finding of this study demonstrated that GEB (200, 400 and 800 mg/kg) alleviated L-dopa induced AIMs in a dose-dependent manner. In each integrative AIM subtype analysis, we also found that the GEB (400 and 800 mg/kg) treatment decreased L-DOPA-induced axial, limb, orolingual, and locomotive AIMs compared to the LID group. In addition, GEB normalized the abnormal LID-induced increase of pERK1/2 and FosB, the immediate early genes of LID in the striatum.ConclusionsIn conclusion, our results provide a novel insight into the pharmacological actions of GEB that could have a benefit for PD patients through the reduction of LID.